The CD4+ alike CD8+ memory T cell compartment diversification reveales CD8+ T cell subsets with cytotoxic and non-cytotoxic properties

CD4+ memory T helper cells are organized in different subsets characterized by distinct functions and chemokine receptor expression patterns induced and maintained by divergent gene programs. We demonstrate here that identical chemokine receptor combinations are sufficient to separate analogous differentiated CD8+ memory T cell subsets with matching cytokine profiles. Tc2, Tc17 and Tc22 type CD8+ T cell subsets, in contrast to classical cytotoxic Tc1 and Tc17+1 cells, possess a CD4 helper type alike phenotype characterized by absent cytotoxicity and SLAMF7 expression as well their ability to express CD40L upon activation. Their highly disparate homing patterns and unique TCR repertoire associates them to distinct immune responses as compared to those cytotoxic CD8+ T cells exert their role in. The dermal T cell gene expression signature and enrichment in psoriasis patients indicates that peripheral helper type CD8+ T cells represent a circulatory variant of skin resident cells. Overall design: mRNA profiles of 5 Tc and 5 Th lymphocyte subpopulations from three different donors